The conventional three columns-four rows telephone keyboard is an example of a widely used one hand keyboard. In many applications such a keyboard would be useful for character generation purposes, provided that the number of character codes which can be generated is sufficient. One solution to the problem of increasing the number of available character codes without increasing the number of keys is to use two or more keys for the code generation of one character.
The main application areas for a one hand keyboard are as follows:
On-line programming. PA0 Word processing systems. PA0 Graphics systems needing one hand to move cursor and one hand to type. PA0 Use of a computer while operating an airplane or other vehicle. PA0 Systems for handicapped people. PA0 Weapons systems requiring communications with a computer. PA0 Small computers requiring a small keyboard (electronic notebook).